Hey Larry I see you are still having fun.
When I faced the same problem I went to the Firestone and used the following document to figure out the current replacement part number:
http://www.firestoneip.com/site-reso...tGuide2010.pdf
I was able to do that based upon measurements of the bellows diameter, end plate diameter, configuration of the bellows and location and size of the air connection.
Then I got ahold of truckspring in Saginaw, Michigan to order them. They were extremely helpful and their prices were low.
Truck Suspension, Bilstein Shocks, Firestone Air Bags, Timbren, Leaf Springs - TruckSpring.com
Even replacing them wasn't as bad as I thought it would be. The big thing is avoiding your coach having a crush on you. It's OK to have a crush on your coach but not the other way around.